Control unit gear or shift program selection of an automatic vehicle gearbox

ABSTRACT

A control unit for the gear or shift program selection of an automatic transmission of a motor vehicle is presented, which has a emergency release mechanism. With this a parking brake of the motor vehicle transmission can be released by an operating device that can be actuated by the driver. A housing ( 3 ) is provided and a selector lever ( 1 ), which can be brought into at least two end positions, in which control unit the operating device of the emergency release mechanism is an integral part of the control unit, and in which the operating device has a detachable stop element ( 7 ). The stop element ( 7 ) is secured in a mount ( 9 ) of the control unit by means of a coded release mechanism ( 15 ) and acts as a movement limitation for the release movement of the parking brake by the operating device of the emergency release mechanism in the non-actuated state. The emergency release mechanism can also be actuated due to this novel design even with the control unit only, and, moreover, increased requirements on theft protection can be met.

FIELD OF THE INVENTION

The present invention pertains to a control unit for the gear or shiftprogram selection of a motor vehicle automatic transmission, which hasan emergency release mechanism, by which a parking brake of the motorvehicle transmission can be released by means of an operating devicethat can be operated by the driver, with a housing and with a selectorlever that can be brought into at least two end positions.

BACKGROUND OF THE INVENTION

Automatic transmissions, for which the operating unit of this type canbe used, usually have a plurality of operating steps, which can bemanually preselected by the driver and are called gears. One of theoperating steps of an automatic transmission is a so-called parkposition. If the park position is selected on the automatic transmissionby means of the control unit, blocking is brought about in thetransmission by suitable measures, so that movement of the vehicle is nolonger possible when the park position is engaged.

However, situations are conceivable in which the vehicle shallnevertheless be moved despite the parking brake being engaged, e.g., fortowing a vehicle that broke down. To remedy this situation, it is knownfrom the state of the art that emergency release mechanisms may beprovided, which make possible the mechanical release of the engagedparking brake. The emergency release mechanisms in question usuallycomprise an operating device, e.g., in the form of a draw lever, bymeans of which the driver can release the parking brake engaged in themotor vehicle transmission by a pulling movement on the operating devicevia a cable. Such an emergency release can thus, of course, additionallyalso release the engagement of the parking brake. Since a vehicle cannotbe stolen by rolling or towing away any longer with the parking brakeengaged, which can be considered to be an effective theft protectionmeasure, an emergency release of the parking brake should be able to beperformed by authorized persons only.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to improve a controlunit of this type such that release of the parking brake is provided,which supports the theft protection measures currently used in motorvehicles, and is also designed in terms of its operation such that theoperating devices that are present individually and are commonly used inthe state of the art for the emergency release mechanism of the parkingbrakes of motor vehicle automatic transmissions can be eliminated.

According to the present invention, the operating device of theemergency release mechanism is an integral part of the control unit andhas a detachable stop element, which is secured in the mount of thecontrol unit by means of a coded release mechanism and is used as amovement limitation for the releasing movement of the parking brake bythe operating device of the emergency release mechanism in thenon-actuated state.

Due to the operating device of the emergency release mechanism beingfully integrated, manufacturing and assembly costs for the separatearrangement of the elements of the emergency release mechanism aresaved, on the one hand, and, moreover, the integration leads to areduction of necessary operating elements for the driver and thus to anergonomically more favorable, clearer handling of the motor vehicletransmission. Moreover, the usual requirements currently imposed interms of theft protection are taken into account to the fill extent dueto the coded release mechanism of the stop element.

It proved to be particularly advantageous that the releasing movement ofthe parking brake takes place by displacing the selector lever for thegear or shift program selection such that the emergency release positionis reached by displacing the selector lever beyond its end positions.Thus, the same operating element in the form of the selector lever isavailable to the driver for both the nominal control of the motorvehicle transmission and the actuation of the emergency release. Theoperating device for the emergency release mechanism is embodied by acontrol element, which is arranged at the selector lever, and thecontrol element is coupled with the parking brake arranged at the motorvehicle transmission by means of a connection member.

Corresponding to an advantageous variant of the subject of the presentinvention, the control element may be designed as a carrier, whichengages a hook-shaped recess on the selector lever as soon as the latterhas been brought into the release position for the parking brake, i.e.,into the emergency release position. The carrier may be coupled with theparking brake by means of, e.g., a cable acting as a connection member,but the present invention is, of course, not limited to this, becauseany mechanical connection is possible. The mechanical embodiment offersan inexpensive possibility of variation according to the presentinvention.

It proved to be advantageous for other fields of application for thecontrol element to be provided with a Hall sensor system at the selectorlever, where the control signal generated by the Hall sensor systemcomprising a Hall sensor and the corresponding permanent magnet is to beconsidered to be an information and monitoring signal for the positionof the parking brake.

The latter embodiment variant offers especially the advantage that theemergency release position of the gearshift lever can be additionallytransmitted to the motor vehicle transmission via the control linesalready present in shift-by-wire shifting mechanisms.

Furthermore, a variant of the present invention, in which a lockingdevice is arranged in the housing of the control unit for fixing theoperating device in the release position for the parking brake isarranged, proved to be advantageous. The locking device ensures thatduring the towing of the vehicle, during which the operating device,preferably the selector lever, is brought into the emergency releaseposition, the selector lever remains in the selected position, andrelocking of the parking brake during towing is thus ruled out. Thelocking device may advantageously comprise here a ratchet lever mountedrotatably in the housing with a recess and a detent arranged in a fixedposition at the selector lever, where the recess and the detent areengaged in the parking brake release position of the selector lever.

The stop element, which must be removed from its mount within thecontrol unit to actuate the release position of the selector lever, canbe secured against unauthorized removal by a release mechanism, whichcan be actuated by a key code. This means, e.g., that the ignition keynecessary for the use of the vehicle must be introduced into the releasemechanism present at the stop element to be able to remove the stopelement and subsequently to actuate the emergency release. Thus, theemergency release can be actuated only by a person who also has theignition key for operating the vehicle. Corresponding to anotheradvantageous embodiment, the release mechanism may be provided with anelectronic coding device. This may comprise, e.g., an alphanumerickeypad, in which a multiple-digit code term is to be entered in order toclear the release mechanism and to make it possible to remove the stopelement.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective external view of the control unit according tothe present invention;

FIG. 2 is a sectional view through the control unit according to thepresent invention in a first shifting end position of the selectorlever;

FIG. 3 is a sectional view of the control unit with the selector leverin the opposite second end positing;

FIG. 4 is a sectional view through the control unit with the selectorlever in the cleared position for the parking brake; and

FIG. 5 is a side view of the control unit with a partial section toillustrate the control elements of the operating device to transmit theemergency release position as well as the gear commands

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, the control unit for the gearor shift program selection of a motor vehicle automatic transmission,which is shown in a perspective view in FIG. 1 has a selector lever 1,which is arranged pivotably around an axis of rotation 2 in a housing 3of the control unit. On the lower side of the housing 3 facing away fromthe selector lever, the housing is provided with a base 4, which is usedto fasten the control unit on a body-side mount of a motor vehicle,which said mount is not shown in detail. The selector lever 1 can bemoved in the longitudinal direction of the housing 3 corresponding tothe arrows P₁ and P₂ because of it being mounted by means of the axis ofrotation 2, so that there are two lateral end positions I and II besidesthe middle position of the selector lever 1 shown in FIG. 1.

FIG. 1 also shows that a holding element 5 for a cable 6 is arranged atthe longitudinal end of the control unit. The holding element 5 is usedto fix and guide one free end of the cable 6 at the housing 3. The otherend of the cable 6, which is not shown, is coupled with a parking brakeon the motor vehicle transmission of the corresponding motor vehicle,which parking brake is not designated specifically because it is knownfrom the state of the art. A stop element 7, which is used in thebuilt-in state shown in FIG. 1 as a movement limitation for the releasemovement of the parking brake by the selector lever 1, can be recognizedat the other end of the control unit facing away from the holdingelement 5. The functions of the stop element 7 in conjunction with anoperating device for actuating the emergency release mechanism for theparking brake will be explained in greater detail in the followingfigures.

FIG. 1 additionally shows that the stop element 7 has a slot-like recess8 for introducing a key on its lop side. By introducing acorrespondingly correctly coded key, a coded release mechanism can beactuated within the stop element by turning the key, so that the stopelement 7 can be removed from its mount 9 within the housing 3 of thecontrol unit.

The sectional view through the housing 3 of the control unit, which isshown in FIG. 2, shows that the selector lever 1 has a gate guide 10 atits free end mounted in the housing 3. The gate guide 10 comprises agate path 11 and a spring-loaded wheel 12 rolling thereon. Thecooperation of the gate path 11 and the wheel 12 causes the selectorlever 1 to have a stable middle position M, whereas the additionallypresent end positions I and II of the selector lever 1 are “unstable”positions, from which the selector lever 1 is automatically returned bythe operator into the stable middle position M. The movement limitationfor the end position I is defined by an elastic rubber buffer 13, whichis accommodated in an associated opening of the housing 3. A rubberbuffer 14, which is fastened at the stop element 7 which can be removedfrom the housing 3, is likewise present for the defined end position IIof the selector lever 1. The release mechanism 15, by which the stopelement 7 is secured within the housing 3 as long as no correctly codedkey has been introduced into the recess 8 of the stop element 7, islocated on the underside of the stop element 7.

FIG. 3 shows the selector lever 1 in its end position II locatedopposite the position 1, with the selector lever 1 being in contact by acontact surface with the rubber buffer 14 of the stop element 7. FIG. 3also shows that a locking device 16 comprising a ratchet lever 17 and adetent 18 arranged at the side wall of the selector lever 1 (see FIG. 4)is accommodated in the housing 3, the ratchet lever 17 being pressed bya spring 23 visible in FIG. 2 with its front free end 20 against thestop element 7.

FIG. 4 shows the control unit in the emergency release position, inwhich the selector lever 1 assumes a farther pivoted position comparedwith position II. The requirement for the possibility of pivoting theselector lever 1 beyond the end position II is the fact that the stopelement 7 was removed from its mount 9 in the housing 3, as is shown inFIG. 4. The removal of the stop element 7 causes, on the one hand, thatthe rubber buffer 14 present at the stop element 7 does not act anylonger as a limitation of the deflection in the direction of arrow P₂ ofthe selector lever 1 and, on the other hand, that due to the absence ofthe stop element 7, the ratchet lever 17 is pivoted upward in thedirection of the selector lever 1 with the support of a spring designedas a leg spring 23 and snaps into the detent 18 arranged laterally atthe selector lever 1 in its upper end position. The snapping in causesthe selector lever 1 to remain in the emergency release position. Therelease movement for the parking brake is brought about by a carrier 19,which is located at the end of the cable 6 protruding into the controlunit. Corresponding to the carrier 19, a hook-shaped opening 21 islocated at the lower end of the selector lever 1, the opening 21 beingused to actuate the carrier with the cable 6 coupled therewith during amovement of the selector lever 1 beyond the end position II into theemergency release position corresponding to the direction of arrow P₂and to release the parking brake coupled with the cable 6 at the othertransmission-side end.

The view in FIG. 5 shows another embodiment variant, in which thecontrol element, which is present at the selector lever 1 as part of theoperating device for the emergency release mechanism, is designed as aHall sensor system. A number of Hall sensors 22, which sensitivelyrespond to magnetic fields and can generate corresponding electroniccontrol signals, are fastened here in the area of the housing wall ofthe control unit. The individual Hall sensors 22 are associated with acorresponding position of the selector lever 1 each. At least onepermanent magnet is fastened to the selector lever 1 itself in such aposition that it sweeps one or more of the Hall sensors 22 during thepivoting of the selector lever 1 or is located opposite the Hall sensorsbelonging to the given position in the individual pivoted positions, sothat an electronic transducer signal can be formed.

Such a transducer signal can also be generated after the removal of thestop element 7 and pivoting of the selector lever 1 beyond the endposition II into the emergency release position by the Hall sensorsbelonging to this position. The command generated to release the parkingbrake of the emergency release mechanism in the motor vehicletransmission can be transmitted electronically via a control electronicsystem and a corresponding cabling, so that the transmission of thecontrol command by means of a cable 6 as shown in the preceding figurescan be eliminated.

It is, of course, conceivable that the control commands for the gears ofthe automatic transmission of the motor vehicle are generated by meansof a Hall sensor system, which is especially advantageous from theviewpoint of wear, but the control commands for the release of theparking brake continue to be transmitted by means of a cable 6, as wasalready shown in FIG. 4, because release also must be guaranteed whenvehicle system voltage is absent or insufficient.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. A motor vehicle automatic transmission gear or shift programselection control unit comprising: a driver actuated operating devicefor an emergency release mechanism, by which a parking brake of themotor vehicle transmission can be released; a housing with a mount; aselector lever which can be brought into at least two end positions, theselector lever being connected to the housing, said operating device ofthe emergency release mechanism being an integral part of the controlunit, said operating device including a detachable stop element with acoded release mechanism, said stop element being secured in said mountof the control unit by means of said coded release mechanism, saiddetachable stop element acting as a movement limitation for the releasemovement of the parking brake by said operating device in thenon-actuated state of the emergency release mechanism, said stop elementand said coded release element being removable from said mount and saidhousing.
 2. A control unit in accordance with claim 1, wherein theoperating device includes a control element at said selector lever, saidcontrol element being coupled with said parking brake arranged at themotor vehicle transmission, by a connection member.
 3. A control unit inaccordance with claim 2, wherein said control element includes a carrierengaging a hook-like opening at said selector lever, upon said selectorlever being brought into a release position for the parking brake.
 4. Acontrol unit in accordance with claim 2, wherein said control elementhas a Hall sensor system to generate an electric indication signal forthe position of the parking brake.
 5. A control unit in accordance withclaim 1, wherein the release movement of the parking brake takes placedue to a displacement of the selector lever beyond a selection endposition.
 6. A control unit in accordance with claim 1, furthercomprising a locking device for fixing the operating device for theparking brake in its release position, said locking device beingarranged in said housing.
 7. A control unit in accordance with claim 6,wherein said locking device has a ratchet lever mounted rotatably insaid housing with a recess and a detent fixed to said selector lever,wherein said recess and said detent are engaged with one another in therelease position of the selector lever for the parking brake.
 8. Acontrol unit in accordance with claim 1, wherein said coded releasemechanism associated with said stop element is secured by means of a keycode.
 9. A control unit in accordance with claim 1, wherein said codedrelease mechanism associated with said stop element is secured by anelectronic coding device.
 10. A motor vehicle automatic transmissiongear or shift program selection control unit comprising: a housing witha mount; a driver actuated operating device for an emergency releasemechanism, by which a parking brake of the motor vehicle transmissioncan be released, said operating device being connected to said housing,said operation device including a detachable stop element secured insaid mount via a coded release mechanism; and a selector lever connectedto said housing, said selector lever being movable into at least two endpositions, said detachable stop element acting as a movement limitationto said selector lever defining one of said two end positions, said stopelement acting as a movement limitation to said operating device to stoprelease movement of the parking brake by said operating device in anon-actuated state of the emergency release mechanism.
 11. A controlunit in accordance with claim 1, further comprising: a locking devicearranged in said housing and including a ratchet lever rotatablyarranged in said housing, said ratchet lever defining a recess; a detentarranged on said selector lever, a spring biasing said ratchet leveragainst said stop element.
 12. A control unit in accordance with claim1, wherein: said stop element includes a rubber buffer.
 13. A controlunit in accordance with claim 12, wherein: said selector lever is incontact with said rubber buffer in one of said end positions.
 14. Acontrol unit in accordance with claim 11, wherein: said stop elementincludes a rubber buffer; said selector lever is in contact with saidrubber buffer in one of said end positions.
 15. A brake releasearrangement for a motor vehicle, the arrangement comprising: a housing;a selector lever pivotally mounted in said housing along a pivot pathbetween first and second ends; a detachable stop element selectivelyarrangable in a first position and a second position, said firstposition being in said housing and in said pivot path, said secondposition being spaced and detached from said housing and said pivotpath, said detachable stop element in said first position blockingmovement of said selector lever into said first end of said pivot pathand limiting movement of said selector lever to a sub-path of said pivotpath; a coded release element selectively fixing said detachable stopelement in, and releasing said detachable stop element from, said firstposition in said housing; a brake disengaging element in said housingand disengaging a brake of the vehicle when said selector lever isarranged at said first end.
 16. An arrangement in accordance with claim15, wherein: a shift element is connected to said selector lever andshifts a transmission of the vehicle when said selector lever is movedin said sub-path.
 17. An arrangement in accordance with claim 16,wherein: said selector lever is movable into a plurality of positions insaid sub-path for shifting the transmission into a plurality of gears.18. An arrangement in accordance with claim 16, wherein: said brakedisengaging element disengages the transmission from a park position.19. An arrangement in accordance with claim 15, wherein: said codedrelease element is formed to repetitively connect and disconnect saidstop element from said housing and said pivot path without significantlydamaging said coded release element.
 20. An arrangement in accordancewith claim 15, wherein: said second position of said stop element iscompletely separatable from said housing, said selector lever and saidpivot path.